This article discusses the use of selection structures in Java, such as if, if-else, if-else-if ladder, and switch, which control the flow of execution based on specific conditions.

In Java and similar object-oriented languages, selection structures are used to control the flow of execution and they are based on conditions. The primary selection structures in Java are if, if-else, if-else-if ladder, and switch. Each serves different purposes depending on the conditions to be evaluated and the functionality needed.

Here are some examples:

if statement:
“The if statement in Java allows you to execute a block of code only if a given condition is true. If the condition is false, the code block is skipped” (Jassal, 2023).

Example:

int age = 20;
if (age >= 18) {
    System.out.println("You are eligible to vote.");
}

if-else statement:
“The if-else statement in Java allows you to execute one block of code if the condition is true, and another block if the condition is false” (Jassal, 2023).

Example:

int score = 75;
if (score >= 60) {
    System.out.println("Pass");
} else {
    System.out.println("Fail");
}

if-else-if ladder:
“The if-else statement in Java allows you to execute one block of code if the condition is true, and another block if the condition is false” (Jassal, 2023).

Example:

int marks = 85;
if (marks < 50) {
    System.out.println("Fail");
} else if (marks >= 50 && marks < 60) {
    System.out.println("D Grade");
} else if (marks >= 60 && marks < 70) {
    System.out.println("C Grade");
} else if (marks >= 70 && marks < 80) {
    System.out.println("B Grade");
} else {
    System.out.println("A Grade");
}

switch statement:
Java has a built-in switch statement, which allows you to perform multi-way branching based on the value of an expression (Jassal, 2023).

Example:

int day = 3;
switch (day) {
    case 1:
        System.out.println("Monday");
        break;
    case 2:
        System.out.println("Tuesday");
        break;
    case 3:
        System.out.println("Wednesday");
        break;
    default:
        System.out.println("Another day");
}

When to Use Each Structure:

• if statement: Opt for this when you need to check a single condition.
• if-else statement: Use this for straightforward yes/no decisions.
• if-else-if ladder: Best suited for checking multiple conditions.
• switch statement: Ideal for checking one variable against various constants. This simplifies the code and makes it more readable.

To summarize, the selection structures in Java such as if, if-else, if-else-if ladder, and switch allow developers to control the flow of execution based on various conditions. Each structure has specific use cases that help in writing clear and efficient code depending on the problem needing to be solved.

Originally published at Alex.omegapy - Medium on October 12, 2024.